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1.
Hepatology ; 2021 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-34773257

RESUMO

Currently there is no FDA-approved drug to treat nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), rates of which are increasing worldwide. Although NAFLD/NASH are highly complex and heterogeneous conditions, most pharmacotherapy pipelines focus on a single mechanistic target. Considering the importance of the gut-liver axis in their pathogenesis, we investigated the therapeutic effect of a long-acting dual agonist of glucagon-like peptide (GLP)-1 and GLP-2 receptors in mice with NAFLD/NASH. C57BL/6J mice were fed a choline-deficient high fat diet/high fructose and sucrose solution. After 16 weeks, mice were randomly allocated to receive vehicle, GLP1-Fc, GLP2-Fc, or GLP1/2-Fc subcutaneously every two days for four weeks. Body weight was monitored, insulin/glucose tolerance tests were performed, feces were collected, and microbiome profiles were analyzed. Immobilized cell systems were utilized to evaluate direct peptide effect. Immunohistochemistry, qPCR, immunoblot analysis, tunnel assay, and biochemical assays were performed to assess drug effects on inflammation, hepatic fibrosis, cell death, and intestinal structures. The mice had well-developed NASH phenotypes. GLP1/2-Fc reduced body weight, glucose levels, hepatic triglyceride levels, and cellular apoptosis. It improved liver fibrosis, insulin sensitivity, and intestinal tight junctions, and increased microvillus height, crypt depth, goblet cells of intestine compared to a vehicle group. Similar effects of GLP1/2-Fc were found in in vitro cell systems. GLP1/2-Fc also changed microbiome profiles. We applied fecal microbiota transplantation (FMT) in order to gain further insight into the mechanism of GLP1/2-Fc-mediated protection. We confirmed that FMT exerted an additive effect on GLP1-Fc group, including the body weight change, liver weight, hepatic fat accumulation, inflammation and hepatic fibrosis. CONCLUSION: A long-acting dual agonist of GLP-1 and GLP-2 receptors is a promising therapeutic strategy to treat NAFLD/NASH.

2.
Nat Metab ; 3(3): 410-427, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33758420

RESUMO

TFEB, a key regulator of lysosomal biogenesis and autophagy, is induced not only by nutritional deficiency but also by organelle stress. Here, we find that Tfeb and its downstream genes are upregulated together with lipofuscin accumulation in adipose tissue macrophages (ATMs) of obese mice or humans, suggestive of obesity-associated lysosomal dysfunction/stress in ATMs. Macrophage-specific TFEB-overexpressing mice display complete abrogation of diet-induced obesity, adipose tissue inflammation and insulin resistance, which is independent of autophagy, but dependent on TFEB-induced GDF15 expression. Palmitic acid induces Gdf15 expression through lysosomal Ca2+-mediated TFEB nuclear translocation in response to lysosomal stress. In contrast, mice fed a high-fat diet with macrophage-specific Tfeb deletion show aggravated adipose tissue inflammation and insulin resistance, accompanied by reduced GDF15 level. Finally, we observe activation of TFEB-GDF15 in ATMs of obese humans as a consequence of lysosomal stress. These findings highlight the importance of the TFEB-GDF15 axis as a lysosomal stress response in obesity or metabolic syndrome and as a promising therapeutic target for treatment of these conditions.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fator 15 de Diferenciação de Crescimento/metabolismo , Resistência à Insulina , Lisossomos/metabolismo , Obesidade/prevenção & controle , Estresse Fisiológico , Tecido Adiposo/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Humanos , Macrófagos/metabolismo , Camundongos , Camundongos Transgênicos , Obesidade/metabolismo
3.
Nat Commun ; 12(1): 183, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420039

RESUMO

We have reported that autophagy is crucial for clearance of amyloidogenic human IAPP (hIAPP) oligomer, suggesting that an autophagy enhancer could be a therapeutic modality against human diabetes with amyloid accumulation. Here, we show that a recently identified autophagy enhancer (MSL-7) reduces hIAPP oligomer accumulation in human induced pluripotent stem cell-derived ß-cells (hiPSC-ß-cells) and diminishes oligomer-mediated apoptosis of ß-cells. Protective effects of MSL-7 against hIAPP oligomer accumulation and hIAPP oligomer-mediated ß-cell death are significantly reduced in cells with knockout of MiTF/TFE family members such as Tfeb or Tfe3. MSL-7 improves glucose tolerance and ß-cell function of hIAPP+ mice on high-fat diet, accompanied by reduced hIAPP oligomer/amyloid accumulation and ß-cell apoptosis. Protective effects of MSL-7 against hIAPP oligomer-mediated ß-cell death and the development of diabetes are also significantly reduced by ß-cell-specific knockout of Tfeb. These results suggest that an autophagy enhancer could have therapeutic potential against human diabetes characterized by islet amyloid accumulation.


Assuntos
Amiloide/metabolismo , Proteínas Amiloidogênicas/metabolismo , Autofagia/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/genética , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Animais , Apoptose/fisiologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Técnicas de Inativação de Genes , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Secretoras de Insulina , Macroautofagia/fisiologia , Camundongos , Camundongos Transgênicos
4.
Autophagy ; 17(3): 761-778, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32167007

RESUMO

Lysosomal Ca2+ contributes to macroautophagy/autophagy, an intracellular process for the degradation of cytoplasmic material and organelles in the lysosomes to protect cells against stress responses. TMBIM6 (transmembrane BAX inhibitor motif containing 6) is a Ca2+ channel-like protein known to regulate ER stress response and apoptosis. In this study, we examined the as yet unknown role of TMBIM6 in regulating lysosomal Ca2+ levels. The Ca2+ efflux from the ER through TMBIM6 was found to increase the resting lysosomal Ca2+ level, in which ITPR-independent regulation of Ca2+ status was observed. Further, TMBIM6 regulated the local release of Ca2+ through lysosomal MCOLN1/TRPML1 channels under nutrient starvation or MTOR inhibition. The local Ca2+ efflux through MCOLN1 channels was found to activate PPP3/calcineurin, triggering TFEB (transcription factor EB) nuclear translocation, autophagy induction, and lysosome biogenesis. Upon genetic inactivation of TMBIM6, lysosomal Ca2+ and the associated TFEB nuclear translocation were decreased. Furthermore, autophagy flux was significantly enhanced in the liver or kidney from starved Tmbim6+/+ mice compared with that in the counter tmbim6-/- mice. Together, our observations indicated that under stress conditions, TMBIM6 increases lysosomal Ca2+ release, leading to PPP3/calcineurin-mediated TFEB activation and subsequently enhanced autophagy. Thus, TMBIM6, an ER membrane protein, is suggested to be a lysosomal Ca2+ modulator that coordinates with autophagy to alleviate metabolism stress.Abbreviations: AVs: autophagic vacuoles; CEPIA: calcium-measuring organelle-entrapped protein indicator; ER: endoplasmic reticulum; GPN: glycyl-L-phenylalanine-beta-naphthylamide; ITPR/IP3R: inositol 1,4,5-trisphosphate receptor; LAMP1: lysosomal associated membrane protein 1; MCOLN/TRPML: mucolipin; MEF: mouse embryonic fibroblast; ML-SA1: mucolipin synthetic agonist 1; MTORC1: mechanistic target of rapamycin kinase complex 1; RPS6KB1: ribosomal protein S6 kinase B1; SQSTM1: sequestosome 1; TFEB: transcription factor EB; TKO: triple knockout; TMBIM6/BI-1: transmembrane BAX inhibitor motif containing 6.

5.
Biochim Biophys Acta Gen Subj ; 1865(3): 129834, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33358864

RESUMO

BACKGROUND: Mitochondria is a key organelle for energy production and cellular adaptive response to intracellular and extracellular stresses. Mitochondrial stress can be evoked by various stimuli such as metabolic stressors or pathogen infection, which may lead to expression of 'mitokines' such as growth differentiation factor 15 (GDF15). SCOPE OF REVIEW: This review summarizes the mechanism of GDF15 expression in response to organelle stress such as mitochondrial stress, and covers pathophysiological conditions or diseases that are associated with elevated GDF15 level. This review also illustrates the in vivo role of GDF15 expression in those stress conditions or diseases, and a potential of GDF15 as a therapeutic agent against metabolic disorders such as NASH. MAJOR CONCLUSIONS: Mitochondrial unfolded protein response (UPRmt) is a critical process to recover from mitochondrial stress. UPRmt can induce expression of secretory proteins that can exert systemic effects (mitokines) as well as mitochondrial chaperons. GDF15 can have either protective or detrimental systemic effects in response to mitochondrial stresses, suggesting its role as a mitokine. Mounting evidence shows that GDF15 is also induced by stresses of organelles other than mitochondria such as endoplasmic reticulum (ER). GDF15 level is increased in serum or tissue of mice and human subjects with metabolic diseases such as obesity or NASH. GDF15 can modulate metabolic features of those diseases. GENERAL SIGNIFICANCE: GDF15 play a role as an integrated stress response (ISR) beyond mitochondrial stress response. GDF15 is involved in the pathogenesis of metabolic diseases such as NASH, and also could be a candidate for therapeutic agent against those diseases.


Assuntos
Envelhecimento/genética , Fator 15 de Diferenciação de Crescimento/genética , Miopatias Mitocondriais/genética , Atrofia Muscular/genética , Hepatopatia Gordurosa não Alcoólica/genética , Obesidade/genética , Envelhecimento/metabolismo , Animais , Modelos Animais de Doenças , Retículo Endoplasmático/genética , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/genética , Regulação da Expressão Gênica , Fator 15 de Diferenciação de Crescimento/metabolismo , Fator 15 de Diferenciação de Crescimento/uso terapêutico , Humanos , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Miopatias Mitocondriais/metabolismo , Miopatias Mitocondriais/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Obesidade/metabolismo , Obesidade/patologia , Resposta a Proteínas não Dobradas
6.
Front Immunol ; 11: 1832, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33013834

RESUMO

Type 1 autoimmune diabetes is an autoimmune disease characterized by specific destruction of pancreatic ß-cells producing insulin. Recent studies have shown that gut microbiota and immunity are closely linked to systemic immunity, affecting the balance between pro-inflammatory and regulatory immune responses. Altered gut microbiota may be causally related to the development of immune-mediated diseases, and probiotics have been suggested to have modulatory effects on inflammatory diseases and immune disorders. We studied whether a probiotic combination that has immunomodulatory effects on several inflammatory diseases can reduce the incidence of diabetes in non-obese diabetic (NOD) mice, a classical animal model of human T1D. When Immune Regulation and Tolerance 5 (IRT5), a probiotic combination comprising Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus reuteri, Bifidobacterium bifidium, and Streptococcus thermophiles, was administered 6 times a week for 36 weeks to NOD mice, beginning at 4 weeks of age, the incidence of diabetes was significantly reduced. Insulitis score was also significantly reduced, and ß-cell mass was conversely increased by IRT5 administration. IRT5 administration significantly reduced gut permeability in NOD mice. The proportion of total regulatory T cells was not changed by IRT5 administration; however, the proportion of CCR9+ regulatory T (Treg) cells expressing gut-homing receptor was significantly increased in pancreatic lymph nodes (PLNs) and lamina propria of the small intestine (SI-LP). Type 1 T helper (Th1) skewing was reduced in PLNs by IRT5 administration. IRT5 could be a candidate for an effective probiotic combination, which can be safely administered to inhibit or prevent type 1 diabetes (T1D).


Assuntos
Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Tipo 1/imunologia , Pâncreas/imunologia , Probióticos/farmacologia , Animais , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 1/patologia , Feminino , Masculino , Camundongos , Camundongos Endogâmicos NOD , Pâncreas/patologia
7.
Biochem Soc Trans ; 48(3): 1213-1225, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32510139

RESUMO

The importance of innate immunity in host defense and inflammatory responses has been clearly demonstrated after the discovery of innate immune receptors such as Toll-like receptors (TLRs) or Nucleotide-binding oligomerization domain-containing protein (Nod)-like receptors (NLRs). Innate immunity also plays a critical role in diverse pathological conditions including autoimmune diseases such as type 1 diabetes (T1D). In particular, the role of a variety of innate immune receptors in T1D has been demonstrated using mice with targeted disruption of such innate immune receptors. Here, we discuss recent findings showing the role of innate immunity in T1D that were obtained mostly from studies of genetic mouse models of innate immune receptors. In addition, the role of innate immune receptors involved in the pathogenesis of T1D in sensing death-associated molecular patterns (DAMPs) released from dead cells or pathogen-associated molecular patterns (PAMPs) will also be covered. Elucidation of the role of innate immune receptors in T1D and the nature of DAMPs sensed by such receptors may lead to the development of new therapeutic modalities against T1D.


Assuntos
Morte Celular , Diabetes Mellitus Tipo 1/imunologia , Imunidade Inata , Padrões Moleculares Associados a Patógenos/imunologia , Animais , Células Dendríticas/metabolismo , Humanos , Inflamação , Ligantes , Macrófagos/metabolismo , Complexo Principal de Histocompatibilidade , Camundongos , Camundongos Endogâmicos NOD , Modelos Genéticos , Fator 88 de Diferenciação Mieloide/metabolismo , Nucleotídeos/metabolismo , Receptores Imunológicos/metabolismo , Transdução de Sinais/imunologia , Receptores Toll-Like/metabolismo
8.
Nat Commun ; 11(1): 2127, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358544

RESUMO

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular events in humans with type 2 diabetes (T2D); however, the underlying mechanism remains unclear. Activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome and subsequent interleukin (IL)-1ß release induces atherosclerosis and heart failure. Here we show the effect of SGLT2 inhibitor empagliflozin on NLRP3 inflammasome activity. Patients with T2D and high cardiovascular risk receive SGLT2 inhibitor or sulfonylurea for 30 days, with NLRP3 inflammasome activation analyzed in macrophages. While the SGLT2 inhibitor's glucose-lowering capacity is similar to sulfonylurea, it shows a greater reduction in IL-1ß secretion compared to sulfonylurea accompanied by increased serum ß-hydroxybutyrate (BHB) and decreased serum insulin. Ex vivo experiments with macrophages verify the inhibitory effects of high BHB and low insulin levels on NLRP3 inflammasome activation. In conclusion, SGLT2 inhibitor attenuates NLRP3 inflammasome activation, which might help to explain its cardioprotective effects.


Assuntos
Inflamassomos/efeitos dos fármacos , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Idoso , Animais , Doenças Cardiovasculares/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Glucose/farmacologia , Humanos , Insulina/metabolismo , Interleucina-1beta/metabolismo , Cetonas/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Pessoa de Meia-Idade , Inibidores do Transportador 2 de Sódio-Glicose , Compostos de Sulfonilureia/farmacologia , Fator de Necrose Tumoral alfa/metabolismo
9.
Mol Cells ; 43(1): 66-75, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31931552

RESUMO

Saturated fatty acids contribute to ß-cell dysfunction in the onset of type 2 diabetes mellitus. Cellular responses to lipotoxicity include oxidative stress, endoplasmic reticulum (ER) stress, and blockage of autophagy. Palmitate induces ER Ca2+ depletion followed by notable store-operated Ca2+ entry. Subsequent elevation of cytosolic Ca2+ can activate undesirable signaling pathways culminating in cell death. Mitochondrial Ca2+ uniporter (MCU) is the major route for Ca2+ uptake into the matrix and couples metabolism with insulin secretion. However, it has been unclear whether mitochondrial Ca2+ uptake plays a protective role or contributes to lipotoxicity. Here, we observed palmitate upregulated MCU protein expression in a mouse clonal ß-cell, MIN6, under normal glucose, but not high glucose medium. Palmitate elevated baseline cytosolic Ca2+ concentration ([Ca2+]i) and reduced depolarization-triggered Ca2+ influx likely due to the inactivation of voltage-gated Ca2+ channels (VGCCs). Targeted reduction of MCU expression using RNA interference abolished mitochondrial superoxide production but exacerbated palmitate-induced [Ca2+]i overload. Consequently, MCU knockdown aggravated blockage of autophagic degradation. In contrast, co-treatment with verapamil, a VGCC inhibitor, prevented palmitate-induced basal [Ca2+]i elevation and defective [Ca2+]i transients. Extracellular Ca2+ chelation as well as VGCC inhibitors effectively rescued autophagy defects and cytotoxicity. These observations suggest enhanced mitochondrial Ca2+ uptake via MCU upregulation is a mechanism by which pancreatic ß-cells are able to alleviate cytosolic Ca2+ overload and its detrimental consequences.


Assuntos
Citosol/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Retículo Endoplasmático/metabolismo , Células Secretoras de Insulina/fisiologia , Mitocôndrias/metabolismo , Animais , Autofagia , Cálcio/metabolismo , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Sinalização do Cálcio , Morte Celular , Linhagem Celular , Humanos , Potencial da Membrana Mitocondrial , Camundongos , Estresse Oxidativo , Palmitatos/metabolismo , RNA Interferente Pequeno/genética
10.
Pigment Cell Melanoma Res ; 33(3): 403-415, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31659857

RESUMO

Autophagy regulates cellular turnover by disassembling unnecessary or dysfunctional constituents. Recent studies demonstrated that autophagy and its regulators play a wide variety of roles in melanocyte biology. Activation of autophagy is known to induce melanogenesis and regulate melanosome biogenesis in melanocytes. Also, autophagy induction was reported to regulate physiologic skin color via melanosome degradation, although the downstream effectors are not yet clarified. To determine the role of autophagy as a melanosome degradation machinery, we administered several autophagy inducers in human keratinocytes and melanocytes. Our results showed that the synthetic autophagy inducer PTPD-12 stimulated autophagic flux in human melanocytes and in keratinocytes containing transferred melanosomes. Increased autophagic flux led to melanosome degradation without affecting the expression of MITF. Furthermore, the color of cell pellets of both melanocytes and keratinocytes was visibly lightened. Inhibition of autophagic flux by chloroquine resulted in marked attenuation of PTPD-12-induced melanosome degradation, whereas the expression of melanogenesis pathway genes and proteins remained unaffected. Taken together, our results suggest that the modulation of autophagy can contribute to the regulation of melanocyte biology and skin pigmentation.


Assuntos
Autofagia , Queratinócitos/metabolismo , Queratinócitos/patologia , Melanócitos/metabolismo , Melanócitos/patologia , Melanossomas/metabolismo , Pigmentação da Pele , Administração Tópica , Autofagossomos/efeitos dos fármacos , Autofagossomos/metabolismo , Autofagia/efeitos dos fármacos , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Proteína Beclina-1/metabolismo , Dipeptídeos/administração & dosagem , Dipeptídeos/farmacologia , Epiderme/efeitos dos fármacos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Queratinócitos/ultraestrutura , Melaninas/biossíntese , Melanócitos/ultraestrutura , Melanossomas/ultraestrutura , Fosforilação/efeitos dos fármacos , Pigmentação da Pele/efeitos dos fármacos
11.
Mol Metab ; 27S: S92-S103, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31500836

RESUMO

BACKGROUND: Elucidation of the basic molecular mechanism of autophagy was a breakthrough in understanding various physiological events and pathogenesis of diverse diseases. In the fields of diabetes and metabolism, many cellular events associated with the development of disease or its treatment cannot be explained well without taking autophagy into account. While a grand picture of autophagy has been established, detailed aspects of autophagy, particularly that of selective autophagy responsible for homeostasis of specific organelles or metabolic intermediates, are still ambiguous and currently under intensive research. SCOPE OF REVIEW: Here, results from previous and current studies on the role of autophagy and its dysregulation in the physiology of metabolism and pathogenesis of diabetes are summarized, with an emphasis on the pancreatic ß-cell autophagy. In addition to nonselective (bulk) autophagy, machinery and significance of selective autophagy such as mitophagy of pancreatic ß-cells is discussed. Novel findings regarding autophagy types other than macroautophagy are also covered, since several types of autophagy or lysosomal degradation pathways other than macroautophagy coexist in pancreatic ß-cells. MAJOR CONCLUSION: Autophagy plays a critical role in cellular metabolism, homeostasis of the intracellular environment and function of organelles such as mitochondria and endoplasmic reticulum. Impaired autophagic activity due to aging, obesity or genetic predisposition could be a factor in the development of ß-cell dysfunction and diabetes associated with lipid overload or human-type diabetes characterized by islet amyloid deposition. Modulation of autophagy of pancreatic ß-cells is likely to be possible in the near future, which would be valuable in the treatment of diabetes associated with lipid overload or accumulation of islet amyloid.


Assuntos
Autofagia , Diabetes Mellitus/metabolismo , Inflamação/metabolismo , Células Secretoras de Insulina/metabolismo , Animais , Diabetes Mellitus/patologia , Humanos , Inflamação/patologia
12.
Sci Rep ; 9(1): 3021, 2019 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-30816234

RESUMO

Prolonged hypokalemia induces a decrease of urinary concentrating ability via down-regulation of aquaporin 2 (AQP2); however, the precise mechanisms remain unknown. To investigate the role of autophagy in the degradation of AQP2, we generated the principal cell-specific Atg7 deletion (Atg7Δpc) mice. In hypokalemic Atg7-floxed (Atg7f/f) mice, huge irregular shaped LC3-positive autophagic vacuoles accumulated mainly in inner medullary collecting duct (IMCD) cells. Total- and pS261-AQP2 were redistributed from apical and subapical domains into these vacuoles, which were not co-localized with RAB9. However, in the IMCD cells of hypokalemic Atg7Δpc mice, these canonical autophagic vacuoles were markedly reduced, whereas numerous small regular shaped LC3-negative/RAB9-positive non-canonical autophagic vacuoles were observed along with diffusely distributed total- and pS261-AQP2 in the cytoplasm. The immunoreactivity of pS256-AQP2 in the apical membrane of IMCD cells was markedly decreased, and no redistribution was observed in both hypokalemic Atg7f/f and Atg7Δpc mice. These findings suggest that AQP2 down regulation in hypokalemia was induced by reduced phosphorylation of AQP2, resulting in a reduction of apical plasma labeling of pS256-AQP2 and degradation of total- and pS261-AQP2 via an LC3/ATG7-dependent canonical autophagy pathway.


Assuntos
Aquaporina 2/metabolismo , Proteína 7 Relacionada à Autofagia/metabolismo , Autofagia/fisiologia , Hipopotassemia/metabolismo , Animais , Regulação para Baixo/fisiologia , Rim/metabolismo , Masculino , Camundongos , Proteínas Associadas aos Microtúbulos/metabolismo , Fosforilação/fisiologia , Proteínas rab de Ligação ao GTP/metabolismo
13.
Cell Death Dis ; 10(2): 78, 2019 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-30692509

RESUMO

Renal fibrosis is the final common pathway of various renal injuries and it leads to chronic kidney disease. Autophagy is a cellular process of degradation of damaged cytoplasmic components and regulates cell death and proliferation. Cellular response during unilateral ureteral obstruction (UUO) is tubular segment specific. Thus the role of autophagy on renal tubulointerstitial fibrosis (TIF) after UUO may be different according to segment of nephron. The role of autophagy during UUO remains unclear especially in distal tubules. In this study, we investigated the role of autophagy in distal tubules on renal TIF using conditional knockout mice in which Atg7 was genetically ablated specifically in distal tubular epithelial cell (TEC). In green fluorescent protein (GFP)-LC3 transgenic mice, GFP-LC3 puncta was highly expressed in distal tubular cells of the obstructed kidneys after UUO. Genetic deletion of Atg7 specifically in distal TEC increased renal tubulointerstial fibrosis and epithelial-mesenchymal transition-like phenotype change after UUO through Smad4-dependent transforming growth factor (TGF)-ß pathway. Distal tubule-specific autophagy-deficient mice increased the accumulation of damaged mitochondria and SQSTM1/p62-positive aggregates in the obstructed kidney and resulted in increased expression of NLRP3 inflammasome, interleukin (IL) 1-ß and caspase-1. Distal TEC-specific Atg7 deletion enhanced apoptosis of TECs after UUO. In summary, our data showed that autophagy in distal TEC plays a protective role in development of renal tubulointerstial fibrosis through regulating the expression of TGF-ß an IL1-ß after UUO.


Assuntos
Fibrose/genética , Inflamassomos/metabolismo , Rim/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Autofagia , Camundongos , Camundongos Knockout , Transdução de Sinais
14.
Biochem Biophys Res Commun ; 508(3): 965-972, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30545632

RESUMO

Renal fibrosis is the final common pathway of various renal injuries and it leads to chronic kidney disease. Recent studies reported that FOXD1-lineage pericyte plays a critical role in tubulointerstitial fibrosis (TIF). However the regulatory mechanisms remain unclear. Autophagy is a cellular process of degradation of damaged cytoplasmic components that regulates cell death and proliferation. To investigate the role of autophagy in FOXD1-lineage pericytes on renal TIF, we generated the FOXD1-lineage stromal cell-specific Atg7 deletion (Atg7△FOXD1) mice. FOXD1-lineage stromal cell-specific Atg7 deletion enhanced renal TIF through Smad-dependent transforming growth factor (TGF)-ß signaling after unilateral ureteral obstruction (UUO). FOXD1-lineage stromal cell-specific Atg7 deletion increased the accumulation of interstitial myofibroblasts and enhanced the differentiation of pericytes into myofibroblasts after UUO. Peritubular capillary rarefaction was accelerated in Atg7△FOXD1 mice after UUO. Atg7△FOXD1 mice increased the accumulation of SQSTM1/p62-positive aggregates in the obstructed kidney and resulted in increased expression of NLRP3 inflammasome, interleukin (IL) 1-ß and caspase-1 signaling pathway, which enhanced apoptosis of interstitial cells after UUO. In summary, our data showed that autophagy in FOXD1-lineage stromal cells plays a protective role in renal TIF through regulating the Smad4 dependent TGF-ß an NLRP3 inflammasome signaling pathway.


Assuntos
Autofagia , Fatores de Transcrição Forkhead/análise , Inflamassomos/metabolismo , Rim/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Animais , Apoptose , Proteína 7 Relacionada à Autofagia/genética , Diferenciação Celular , Linhagem da Célula , Fibrose , Fatores de Transcrição Forkhead/genética , Rim/citologia , Rim/metabolismo , Masculino , Camundongos , Camundongos Knockout , Miofibroblastos/citologia , Pericitos/citologia , Receptores do Fator de Crescimento Derivado de Plaquetas/análise , Transdução de Sinais , Proteínas Smad/metabolismo , Células Estromais/química , Obstrução Ureteral/complicações
15.
Artigo em Inglês | MEDLINE | ID: mdl-30197624

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is an emerging global health problem and a potential risk factor for type 2 diabetes, cardiovascular disease, and chronic kidney disease. Nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD, is a predisposing factor for development of cirrhosis and hepatocellular carcinoma. The increasing prevalence of NASH emphasizes the need for novel therapeutic approaches. Although therapeutic drugs against NASH are not yet available, fundamental insights into the pathogenesis of NASH have been made during the past few decades. Multiple therapeutic strategies have been developed and are currently being explored in clinical trials or preclinical testing. The pathogenesis of NASH involves multiple intracellular/extracellular events in various cell types in the liver or crosstalk events between the liver and other organs. Here, we review current findings and knowledge regarding the pathogenesis of NASH, focusing on the most recent advances. We also highlight hormone-based therapeutic approaches for treatment of NASH.

16.
Diabetes ; 67(9): 1892-1902, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29941447

RESUMO

We investigated ethnicity-specific exonic variants of type 2 diabetes (T2D) and its related clinical phenotypes in an East Asian population. We performed whole-exome sequencing in 917 T2D case and control subjects, and the findings were validated by exome array genotyping in 3,026 participants. In silico replication was conducted for seven nonsynonymous variants in an additional 13,122 participants. Single-variant and gene-based association tests for T2D were analyzed. A total of 728,838 variants were identified by whole-exome sequencing. Among nonsynonymous variants, PAX4 Arg192His increased risk of T2D and GLP1R Arg131Gln decreased risk of T2D in genome-wide significance (odds ratio [OR] 1.48, P = 4.47 × 10-16 and OR 0.84, P = 3.55 × 10-8, respectively). Another variant at PAX4 192 codon Arg192Ser was nominally associated with T2D (OR 1.62, P = 5.18 × 10-4). In T2D patients, PAX4 Arg192His was associated with earlier age at diagnosis, and GLP1R Arg131Gln was associated with decreased risk of cardiovascular disease. In control subjects without diabetes, the PAX4 Arg192His was associated with higher fasting glucose and GLP1R Arg131Gln was associated with lower fasting glucose and HbA1c level. Gene-based analysis revealed that SLC30A8 was most significantly associated with decreased risk of T2D (P = 1.0 × 10-4). In summary, we have identified nonsynonymous variants associated with risk of T2D and related phenotypes in Koreans.


Assuntos
Diabetes Mellitus Tipo 2/genética , Predisposição Genética para Doença , Variação Genética , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Proteínas de Homeodomínio/genética , Fatores de Transcrição Box Pareados/genética , Polimorfismo de Nucleotídeo Único , Idoso , Alelos , Substituição de Aminoácidos , Grupo com Ancestrais do Continente Asiático , Estudos de Casos e Controles , Estudos de Coortes , Biologia Computacional , Bases de Dados Genéticas , Diabetes Mellitus Tipo 2/metabolismo , Sistemas Especialistas , Feminino , Frequência do Gene , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Receptor do Peptídeo Semelhante ao Glucagon 1/química , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Transcrição Box Pareados/química , Fatores de Transcrição Box Pareados/metabolismo , República da Coreia , Sequenciamento Completo do Exoma
17.
Sci Rep ; 8(1): 6789, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29717162

RESUMO

Growth differentiation factor 15 (GDF15) is an endocrine hormone belonging to the TGFß superfamily member. GDF15 administration or GDF15 overexpression has been reported to have anti-obesity and anti-diabetic effects. Although non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH) is frequently associated with obesity and insulin resistance, the functional role of endogenous GDF15 and therapeutic effect of GDF15 overexpression in NASH and related metabolic deterioration have not been evaluated. Here, we found that GDF15 expression was increased in the livers of NASH animal models and human subjects with NASH. Elevated expression of GDF15 was due to diet-induced hepatic endoplasmic reticulum (ER) stress. Gdf15-knockout mice exhibited aggravated NASH phenotypes such as increased steatosis, hepatic inflammation, fibrosis, liver injury, and metabolic deterioration. Furthermore, GDF15 directly suppressed expression of fibrosis-related genes and osteopontin (OPN), contributing factors for NASH-related fibrosis, in hepatic stellate cells in vitro and in the liver of mice in vivo. Finally, we found that GDF15-transgenic mice showed attenuation of NASH phenotypes and metabolic deterioration. Therefore, our results suggest that induction of endogenous GDF15 is a compensatory mechanism to protect against the progression of NASH and that GDF15 could be an attractive therapeutic candidate for treatment of NASH and NASH-related metabolic deterioration.


Assuntos
Deficiência de Colina/genética , Estresse do Retículo Endoplasmático/genética , Fator 15 de Diferenciação de Crescimento/genética , Células Estreladas do Fígado/metabolismo , Cirrose Hepática/genética , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Actinas/genética , Actinas/metabolismo , Animais , Deficiência de Colina/metabolismo , Deficiência de Colina/patologia , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Dieta/efeitos adversos , Modelos Animais de Doenças , Regulação da Expressão Gênica , Fator 15 de Diferenciação de Crescimento/deficiência , Células Estreladas do Fígado/patologia , Humanos , Fígado/patologia , Cirrose Hepática/etiologia , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Masculino , Metionina/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Osteopontina/genética , Osteopontina/metabolismo , Cultura Primária de Células , Transdução de Sinais , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo
18.
Nat Commun ; 9(1): 1438, 2018 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-29650965

RESUMO

Autophagy is a critical regulator of cellular homeostasis, dysregulation of which is associated with diverse diseases. Here we show therapeutic effects of a novel autophagy enhancer identified by high-throughput screening of a chemical library against metabolic syndrome. An autophagy enhancer increases LC3-I to LC3-II conversion without mTOR inhibition. MSL, an autophagy enhancer, activates calcineurin, and induces dephosphorylation/nuclear translocation of transcription factor EB (TFEB), a master regulator of lysosomal biogenesis and autophagy gene expression. MSL accelerates intracellular lipid clearance, which is reversed by lalistat 2 or Tfeb knockout. Its administration improves the metabolic profile of ob/ob mice and ameliorates inflammasome activation. A chemically modified MSL with increased microsomal stability improves the glucose profile not only of ob/ob mice but also of mice with diet-induced obesity. Our data indicate that our novel autophagy enhancer could be a new drug candidate for diabetes or metabolic syndrome with lipid overload.


Assuntos
Autofagia/efeitos dos fármacos , Diabetes Mellitus/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Síndrome Metabólica/tratamento farmacológico , Oxazóis/uso terapêutico , Animais , Diabetes Mellitus/metabolismo , Diabetes Mellitus/patologia , Células HeLa , Humanos , Hipoglicemiantes/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Síndrome Metabólica/metabolismo , Síndrome Metabólica/patologia , Metaboloma/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Oxazóis/química , Estresse Fisiológico/efeitos dos fármacos
19.
Mol Cells ; 41(1): 1-2, 2018 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-29385789
20.
Mol Cells ; 41(1): 11-17, 2018 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-29370692

RESUMO

Autophagy is critical for the maintenance of organelle function and intracellular nutrient environment. Autophagy is also involved in systemic metabolic homeostasis, and its dysregulation can lead to or accelerate the development of metabolic disorders. While the role of autophagy in the global metabolism of model organisms has been investigated mostly using site-specific genetic knockout technology, the impact of dysregulated autophagy on systemic metabolism has been unclear. Here, we review recent papers showing the role of autophagy in systemic metabolism and in the development of metabolic disorders. Also included are data suggesting the role of autophagy in human-type diabetes, which are different in several key aspects from murine models of diabetes. The results shown here support the view that autophagy modulation could be a new modality for the treatment of metabolic syndrome associated with lipid overload and human-type diabetes.


Assuntos
Autofagia/fisiologia , Diabetes Mellitus/fisiopatologia , Metabolismo Energético/fisiologia , Doenças Metabólicas/fisiopatologia , Homeostase/fisiologia , Humanos , Inflamação/fisiopatologia , Resistência à Insulina/fisiologia , Modelos Biológicos , Obesidade/fisiopatologia
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